摘要:
Butadiene copolymers are brominated using certain quaternary ammonium tribromides as the brominating agent. The bromination process proceeds easily under mild conditions, and produces a brominated product that has excellent thermal stability.
摘要:
Butadiene copolymers are brominated in solution using bromine as the brominating agent. The bromination is conducted in the presence of an excess of an aliphatic alcohol, relative to the amount of bromine that is used. The bromination proceeds rapidly at mild conditions, and is selective in that only aliphatic carbon-carbon double bonds are brominated, and unwanted bromination at tertiary carbon atoms is largely or completely avoided. The resulting brominated polymers are characterized in having very good thermal stability.
摘要:
Butadiene polymers are brominated using a quaternary ammonium or quaternary phosphonium tribromide as the brominating agent. The bromination is performed in a solvent mixture than contains at least one polyhalogenated alkane and at least one monohalogenated alkane. The process proceeds easily under mild conditions and allows high conversions to be achieved easily.
摘要:
Compounds or polymers that contain carbon-carbon unsaturation are brominated using a quaternary phosphonium tribromide as the brominating agent. The bromination process proceeds easily under mild conditions. The process can be highly selective. When the substrate is a butadiene polymer or copolymer, the brominated product tends to have excellent thermal stability.
摘要:
New synthetic procedures for preparing insecticidal 3-(substituted phenyl)-5-(thienyl or furyl)-1,2,4-triazoles utilizing thioimidate intermediate.
摘要:
An ester of a sugar and a brominated fatty acid is a useful FR additive for combustible polymers. The brominated FR additives unexpectedly are stable at the extrusion temperatures, and provide excellent flame retardancy to the combustible polymers.
摘要:
4,6-Dinitroresorcinol is prepared by reacting resorcinol with concentrated nitric acid that is substantially free of suboxides of nitric acid. It has been found that greater than 60 percent yields of the desired product can be obtained when the concentration of aqueous nitric acid used is between about 80 and about 93 weight percent, and the concentration of suboxides is less than about 2 weight percent based on the weight of nitric acid.
摘要:
A process for the efficient manufacture of 2-alkyl-5-hydroxypyrimidines from relatively inexpensive raw materials is provided.The vapor phase condensation/cyclization of 1,3-diamino-2-propanol and an alkanecarboxylic acid produces an equilibrium mixture of 2-alkyl-5-hydroxytetrahydropyrimidine and 2-alkyl-5-(aminomethyl)oxazoline. After separation from the oxazoline, the tetrahydropyrimidine can be dehydrogenated under mild neutral conditions with manganese dioxide to produce 2-alkyl-5-hydroxypyrimidines.
摘要:
The useful life of the palladium dehydrogenation catalyst used in the preparation of 2-alkylpyrimidines from 1,3-diaminopropane and an appropriate alkanecarboxylic acid in a continuous vapor phase process is substantially increased by employing a stoichiometric excess of the carboxylic acid and by using catalyst pellets of less than 3-4 mm diameters. Additionally, the dehydrogenation catalyst can be regenerated in situ by controlled air oxidation below 350.degree. C.